Recent advances in optics provide for a method of exposure of materials on a length scale much smaller than previously realized. Such near-field optical methods are realized by placing an aperture or a lens in close proximity to the surface of the sample or material to be exposed. Special methods for positioning control of the aperture or lens are required, as the distance between the optical elements (aperture or lens) and the material surface is extremely small. Betzig and Trautman in U.S. Pat. No. 5,272,330 reported on the use of tapered optical fibers as a means of providing exposures in extremely small areas; exposures of the size of 10 nm in area are now relatively commonplace. In this case, the fiber tip position is maintained to be within some nanometers (typically 10-50) of the target surface. Others (see, for example, the review by Q. Wu, L. Ghislain, and V. B. Elings, Proc. IEEE (2000), 88(9), pg. 1491-1498) have developed means of exposure by the use of the solid immersion lens (SIL). The SIL is positioned within approximately 0.3 micrometer of the target surface by the use of special nano-positioning technology as in the case of the tapered optical fiber. SIL technology offers the advantage that the lens provides a true imaging capability, i.e. features in a real object can be faithfully rendered in an image of reduced spatial extent. In the case of the SIL, images can be produced much smaller than the image size achievable through the use of conventional or classical optics. Such conventional optics is said to be diffraction-limited because the size of the smallest feature in an image is limited by the physical diffraction. Exposures produced by means of the SIL or other near-field optical methods can be much smaller in spatial extent than those produced by conventional optical systems and still be readable. Near-field optics has been used to create single marks in recording media and used to capture images not capable of being captured using a conventional optical microscope. A problem of the prior art image storage is that it relies on a single method for retrieving the image. For example; in a digital data storage system the data is encoded in a digital file, while in an optical system an analog image is recorded. When the digital file is written, a protocol or hierarchical file structure is used to specify to the reading device how the data has been written. Over time, different methods of recording or writing, including different means of encoding the data in digital files evolve and the devices and media used to read the files may change and become obsolete. When this happens it becomes very difficult if not impossible to retrieve these files. In the case where images are used as the means for recording and storing data, larger amounts of storage space on the recording medium and different materials are required for recording and storing the data compared to digital methods.
Near-field technology as used in the present invention provides a means of exposure to be used in the production of small images and to use these images for the production of a novel image storage system capable of mixed analog and digital means of storage. Such a mixed mode storage system has the advantage of providing image storage with retrieval means independent of digital storage format specifications, while requiring less space than conventional image storage means.